Recent work in this laboratory has shown: (1) that certain mouse and human cancer cells in culture secrete nerve growth factor; (2) that normal fibroblasts secrete nerve growth factor in culture; (3) that the action of nerve growth factor is not confined to the nervous system. In addition to its long-known effects on the nervous system, our findings indicate that nerve growth factor also operates upon lymphocytes in immune reactions, and further that it can stimulate the growth of blood vessels. In this connection, it is possible that nerve growth factor and "tumor angiogenesis factor" are related to one another; (4) that nerve growth factor is present in significant concentrations in human serum, and that its level is elevated in Von Recklinghausen's disease. Using chemical, immunologic and biologic methods and assays, we propose to study (1) the biological function and mechanism of action of nerve growth factor; (2) to study the action of this factor upon the vascular and immune systems; (3) to study the nerve growth factor of, and its secretion by, certain neoplastic tumors of man; (4) to study the production of nerve growth factor by normal and malignant fibroblasts; (5) to explore the possibility that this factor may be important in the process of wound healing.